2.7.10 glibc double free detected

[wcolburnnrao]

BPO	25463
Nosy	@amauryfa, @zware
Files	debug.sh

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2020-04-27.01:50:48.825>
created_at = <Date 2015-10-22.21:08:22.235>
labels = ['interpreter-core', 'type-crash']
title = '2.7.10 glibc double free detected'
updated_at = <Date 2020-04-27.01:50:48.824>
user = 'https://bugs.python.org/wcolburnnrao'

bugs.python.org fields:

activity = <Date 2020-04-27.01:50:48.824>
actor = 'zach.ware'
assignee = 'none'
closed = True
closed_date = <Date 2020-04-27.01:50:48.825>
closer = 'zach.ware'
components = ['Interpreter Core']
creation = <Date 2015-10-22.21:08:22.235>
creator = 'wcolburnnrao'
dependencies = []
files = ['41454']
hgrepos = []
issue_num = 25463
keywords = []
message_count = 6.0
messages = ['253354', '253355', '257242', '257254', '257256', '367347']
nosy_count = 3.0
nosy_names = ['amaury.forgeotdarc', 'zach.ware', 'wcolburnnrao']
pr_nums = []
priority = 'normal'
resolution = 'out of date'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'crash'
url = 'https://bugs.python.org/issue25463'
versions = ['Python 2.7']

[wcolburnnrao]

Linking cython against the static libpython in a python install compiled with shared libraries causes a glibc error that a double free or corruption was found while importing site. I don't think it is cython's fault.

Happens on RHEL6.6.
Linux anotheruvula 2.6.32-504.30.3.el6.x86_64 #1 SMP Thu Jul 9 15:20:47 EDT 2015 x86_64 x86_64 x86_64 GNU/Linux
gcc (GCC) 4.4.7 20120313 (Red Hat 4.4.7-11)

I am attaching a shell script which demonstrates the problem.

[wcolburnnrao]

I don't see the shell script attached anywhere.

I'll just paste it here!

-----cut here-----
PYDEST=pwd

wget https://www.python.org/ftp/python/2.7.10/Python-2.7.10.tgz
wget http://cython.org/release/Cython-0.23.4.tar.gz

rm -rf Python-2.7.10 Cython-0.23.4 ${PYDEST}/pybug

tar xvf Python-2.7.10.tgz
cd Python-2.7.10
LD_RUN_PATH=$PYDEST/pybug/lib:$LD_LIBRARY_PATH
export LD_RUN_PATH
./configure --prefix=$PYDEST/pybug --enable-shared
make -j 8
make install prefix=$PYDEST/pybug
cd ..
tar xvf Cython-0.23.4.tar.gz
cd Cython-0.23.4
$PYDEST/pybug/bin/python2.7 setup.py install
cd ..

cat > crash.py <<EOF
print 'hello world'
EOF

${PYDEST}/pybug//bin/cython --embed crash.py
gcc -g crash.c -I${PYDEST}/pybug/include/python2.7 ${PYDEST}/pybug/lib/python2.7/config/libpython2.7.a -lm -ldl -lutil -lpthread -o doublefree

## *** glibc detected *** ./doublefree: double free or corruption (out): 0x00007f57fb8c5030 ***
## crashes in PyInitialize() during "import site"

./doublefree

[wcolburnnrao]

I tried the test with Python 2.7.11, and it still crashes.

[amauryfa]

I don't reproduce the crash, but I noticed that the binary imports and executes the system's /usr/lib/python2.7/site.py.

I think it's cython's fault (or maybe the way you use it): "cython --embed" is not really isolated from the rest of the system, so it can only be used with the system's Python.

[wcolburnnrao]

wcolburn@anotheruvula</home/anotheruvula/python/debug>$ strace doublefree 2>&1 | grep site.py
open("/home/anotheruvula/python/debug/pybug/lib/python2.7/site.py", O_RDONLY) = 3
open("/home/anotheruvula/python/debug/pybug/lib/python2.7/site.pyc", O_RDONLY) = 4
*** glibc detected *** doublefree: double free or corruption (out): 0x00007fa1eb491030 ***
======= Backtrace: =========

It's pulling in it's own site.py, not the system site.py when I do it.

[zware]

As Python 2.7 is now at end-of-life, I'm closing this issue. If you can still reproduce the problem with a modern version of Python (3.6-3.8), please reopen it.